Polyalkenamers and process for the preparation thereof

ABSTRACT

1. A PROCESS FOR THE PRODUCTION OF POLYALKENAMERS BY THE CATALYZED RING-OPENING POLYMERIZATION OF CYCLIC OLEFINS EMPLOYING A CATALYST CONTAINING A METAL OF SUBGROUPS 5 TO 7 OF THE PERIODIC TABLE WHICH COMPRISES CONDUCTING THE POLYMERIZATION IN THE PRESENCE OF AN UNSATURATED CARBOXYLIC ACID ESTER WHEREIN THE ESTER GROUP IS SEPARATED FROM THE DOUBLE BONDED CARBON ATOM BY AT LEAST ONE METHYLENE GROUP OR THE SINGLE BONDED OXYGEN ATOM OF THE ESTER GROUP AND AT LEAST ONE OF THE CARBON ATOMS HAVING THE DOUBLE BOND HAS AT LEAST ONE HYDROGEN ATOM.

United States Patent l US. Cl. 260-677 R 17 Claims ABSTRACT OF THE DISCLOSURE Polyalkenamers are produced by a ring-opening polymerization of cyclic olefins employing a catalyst containing a metal of Subgroups 5 to 7 of the periodic table and conducting the polymerization in the presence of an unsaturated carboxylic acid ester wherein the ester group is separated from the double bonded carbon atom by at least one methylene group or the single bonded oxygen atom of the ester group and at least one of the carbon atoms bearing the double bond bears at least one hydrogen atom.

BACKGROUND OF THE INVENTION This is a division, of application Ser. No. 152,374, filed June 11, 1971, now US. Pat. No. 3,798,175.

This invention relates to a process for the preparation of polyalkenamers by the ring-opening polymerization of cyclic olefins employing a catalyst containing a metal of Subgroups 5 through 7 of the periodic table or a compound thereof and to novel polyalkenamers thus-produced.

It is known the cyclic olefins containing at least one unsubstituted ring double bond can be polymerized under ring-opening conditions. The catalysts employed for this ring-opening polymerization are supported catalysts which contain a metal of Subgroups 5 through 7 of the periodic table, or the compounds thereof. See German Published Application DAS 1,072,811. Preferred catalysts are the reaction products of compounds of the above-mentioned metals with organometallic compounds or hydrides of metals of Main Groups 1 through 3 or Subgroup 2 of the periodic table, as well as optionally compounds which contain one or more hydroxy and/ or sulfhydryl groups. See French Patents 1,394,380 and 1,467,720; and published disclosures of Dutch Patent Applications 6510,331; 6605,105; 6614,413; 67-04,424; 68-06,208; and 68- 06,211. The catalysts described therein contain compounds of molybdenum or tungsten and, as organometallic compounds, usually organoaluminum compounds. According to the published texts of Dutch Patent Applications 67- 14,559 and 6806,209, vanadium, niobium, tantalum, rhenium, technetium, or manganese can also be components of such catalyst systems.

In accordance with German Unexamined Published Application DOS 1,909,226, it is also possible to employ catalyst systems containing a halide or an oxyhalide of molybdenum or tungsten wherein the stage of oxidation of the metal is 4, 5 or 6, an aluminum trihalide.

With the aid of these catalysts, a great variety of polymers can be prepared with structures which are strictly regular along the polymer chains, the structure of the polymer units being exclusively dependent on the cycloolefin employed as the monomer. Thus, it is possible, for example, to produce linear polymers by the polymerization of monocyclic ole'fins; polymers having'recurring polymer units containing a single ring by the polymerization of bicyclic olefins; and, in general, polymers having recurring polymer units which contain one ring less than the starting monomer by the polymerization of polycyclic olefins.

3,849,509 Patented Nov. 19, 1974 The polyalkenamers produced by the polymerization of monocyclic olefins are of particular interest for the additional reason that, depending on the cycloolefin employed, it is possible to prepare polymers having differing double bond content. Thus, polybutenamers which are free of vinyl groups, i.e., pure 1,4-polybutadienes, are obtained from cyclobutene, 1,5-cyclooctadiene, and 1,5,9-cyclododecatriene. Polypentenamers are obtained from cyclopentene which have three -CH -groups disposed between the double bonds. Polyoctenamers are produced from cyclooctene which correspond to a completely regular semi-hydrogenated 1,4-polybutadiene. Polydecenamers are prepared from cyclododecene corresponding to a two thirds hydrogenated 1,4-polybutadiene in which remaining double bonds are arranged in the molecule at regular intervals. Accordingly, it is possible to produce polymers, the structures of which represent variations from pure 1,4- polybutadienes, free of vinyl groups, to strictly linear polyethylenes or polymethylenes.

It is likewise known that the average molecular weight or the degree of polymerization of a polymer afiects properties of the polymer and thus its usefulness in any particular field of application, as well as its characteristics during the production and processing. Thus, polymer solutions of equal weight concentration of polymer are more viscous, the higher the molecular weight of the polymer in solution. Thus, difiiculties are encountered with solutions of very high-molecular polymers, e.g., during the polymerization, for example, in the mixing or obtaining satisfactory heat exchange, and increased energy requirements for the agitating step result. Also, the further processing of very high-molecular polymers is difficult. For this reason, they are often degradated mechanically, chemically, or thermally prior to the final shaping procedure, e.g., injectionmolding, extrusion, or calendering.

The polyalkenamers obtained during the ring-opening polymerization of cycloolefins are normally very highmolecular. Because of the above-described difliculites with polymers of very high molecular weight, attempts have been made in the prior art to develop processes for regulating the molecular weight of the polymers producible by a great variety of polymerization methods. In the polymerization of a-olefins with organometallic mixed catalysts, the so-called hydrogen regulation, i.e., polymerization in the presence of a certain partial hydrogen pressure, proved useful. Other possibilities for controlling the molecular weight of a-olefin polymers were varying the catalyst components, elevating the temperature or adding alkylzinc or al-kylcadmium compounds during the polymerization.

Although organometallic mixed catalysts or related catalyst systems are also employed in the ring-opening polymerization of cycloolefins, the methods for molecular weight regulation employed in the polymerization of the a-olefins either are unsuccessful or exhibit definite disadvantages which make the use of such methods diflicult, if not impossible. Thus, hydrogen, for example, up to an excess pressure of 4 atmospheres exerts practically no influence at all on the molecular weight of the polyalkenamers prepared by the ring-opening polymerization of cycloolefins. Even if hydrogen were efiective at pressures higher than those mentioned above, the hydrogen regulating method would require increased investment costs, since the plant would have to be designed for pressures which do not occur in the unregulated ring-Opening polymerization of the cycloolefins which, under normal pressure, are present in the liquid phase or in solution at the polymerization temperature. Although the molecular weight of the polyalkenamers can be reduced by employing a higher polymerization temperature, the yield and the steric uniformity of the polymers are impaired in so doing. Moreover, due to the temperature sensitivity of the mixed catalysts customarily employed for the ring-opening polymerization of cycloolefins, such catalysts become inactive above 40-50 C. in a short period. Also, modifications of an optimal catalyst system can strongly impair yield. See, for example, Dutch Patent Application 6605,l05, p. 16.

The last of the above-mentioned methods for controlling the molecular weight during the polymerization of u-OlefiIlS with organometallic mixed catalysts, i.e., using an alkylzinc or alkylcadmium compound as the controlling agent, is of little practical use, even if it were effective in the ringopening polymerization of cycloolefins, because such zinc and cadmium compounds are very toxic and can be prepared only with difficulty and thus are expensive.

The only process heretofore known wherein polymers are obtained which exhibit improved processability is described in Britsh Patent 1,098,340. In ths process, cyclic monoolefins are copolymerized under ring-opening in the presence of a conjugated diolefin, such as, for example, butadiene, isoprene, or 1,3-pentadiene. The thus-produced copolymers contain polymer units derived from both the cycloolefin and the conjugated diole fin, in varying molar ratios.

As shown in Comparative Experiments N through T in Table 3, conjugated dienes, although they influence the molecular weight of the polyalkenamers produced in polymerizations conducted in their presence, also are more or less strong catalyst poisons. Thus, for example, the presence of only 1 mol% of 1,3-butadiene, 5 mol% of isoprene, 5 mol% of 2,3-dimethyl-1,3-butadiene, or mol% of 2,4-hexadiene, results in the complete inhibition of the polymerization catalyst and no polymer is obtained. Cyclic conjugated diolefins also cause a pronounced lowering of the yield of polymer. Moreover, it is not possible using such dienes as polymerization regulators to produce polymers which are waxy or oil-like products having very low molecular weights, e.g., about 500-5000.

In our prior filed Application SJN. 70,497 (Huels 207) filed Sept. 8, 1970, we claim a process for the regulation of molecular weight of polyalkenamers by the addition of monoolefins, preferably ot-olefins, during the polymerization. The molecular weight of polyalkenamers can be regulated with a very high degree of success by this process. However, there is a great interest in polymers having functional terminal groups, which can be employed for further reactions, such as, for example, cross-linking reactions or for the construction of other defined polymer structures, e.g., block copolymers or stellate polymers. For example, a stellate structure is obtained by the reaction of a unilaterally lithium-terminated polymer, e.g., a polybutadiene or polystyrene produced in a polymerization which employs butyllithium as the catalyst, with a trior tetrahalogen compound, such as, for example, methyltrichlorosilane, silicon tetrachloride, or carbon tetrabromide. A chain of a polymer terminating at both ends in halogen can be reacted with a unilaterally metalterminated chain of another polymer to form block copolymers. Polymer chains terminating in hydroxyl groups can be cross-linked with di-, tri-, or polyisocyanates or other polyfunctional compounds, such as, for example, acid chlorides of polybasic acids. These examples are typical but not complete and merely illustrate that such reactions of telechelic polymers (U.S. 3,244,664) have gained increasing importance in recent times. Functional end groups also often influence the practical application properties of the polymers and effect, for example, an

jects will be apparent to those skilled in the art to which this invention pertains.

SUMMARY OF THE INVENTION According to this invention, the molecular weight of polyalkenamers produced by the ring-opening polymerization of cyclic olefins employing a catalyst containing a metal of Subgroups 5 to 7 of the periodic table and conducting the polymerization in the presence of an unsaturated carboxylic acid ester wherein the ester group is separated from the double bonded carbon atom by at least one methylene group or the single bonded oxygen atom of the ester group and at least one of the carbon atoms bearing the double bond bears at least one hydrogen atom.

DETAILED DISCUSSION The cyclic olefin and cycloolefin employed in the process of this invention are unsaturated hydrocarbons containing one or more rings, at least one of which contains at least one unsubstituted non-conjugated double bond.

The cycloolefins polymerized according to the process of this invention preferably contain 4 to 12 ring carbon atoms and a total of 4 to 20, preferably 4 to 15 carbon atoms; from 1 to 3, preferably 1 to 2 rings, which can be fused or separate cycloaliphatic rings; whose ring carbon atoms are unsubstituted or one or more of which are substituted with lower-alkyl, e.g., of 1 to 4 carbon atoms, cycloalkyl, e.g., of 5 to 7 carbon atoms, or aryl, alkaryl or aralkyl, e.g., of 6 to 10 carbon atoms.

Preferred classes of starting cycloolefins are the followa) those containing 1 to 2 non-conjugated double bonds, preferably one;

(b) those containing 1 to 2 rings, preferably one;

(c) those of (a) and (b) containing two fused rings;

(d) those of (a), (b), and (c) containing 0-21oweralkyl groups as the sole substituents on the ring carbon atoms, preferably 0;

(e) those of (d) containing 1-2 methyl groups as the sole substituents on the ring carbon atoms;

(f) those of (a), (b), (c), (d), and (e) wherein the unsaturated carbon atoms each bear a hydrogen atom; and

(g) those of (a), (b) (c), (d), (e) and (f) wherein the ring of the cycloolefin containing the unsaturation contains 5 or 7 to 12 ring carbon atoms.

Examples of cycloolefins which can be polymerized according to the process of this invention are cyclobutene, cyclopentene, cycloheptene, cyclooctene, cyclononene, cyclodecene, cycloundecene, cyclododecene, cis, cis-1,5- cylooctadiene, 1 methyl 1,5 cyclooctadiene, 3,7-dimethyl 1,5 cyclooctadiene, 1,5,9 cyclododecatriene, 4,5 dimethyl 1,4,7 cyclodecatriene, cis, trans 1,5- cyclodecadiene, norbomene, dicyclopentadiene, dihydrodicyclopentadiene, and 4-phenylcylooctene, and mixtures thereof. Cycloolefins which cannot be polymerized with ring-opening, e.g., cyclohexene and the derivatives thereof, are not employed as starting monomers in the polymerization process of this invention.

The polymerization of this invention is conducted in the presence, as a polymerization regulator, of an unsaturated carboxylic acid ester containing at least one acyclic carbon-carbon double bond, i.e., wherein the double bond is not part of a ring, which is separated from the carbonyl group of the ester grouping by at least one ,single bonded carbon atom, e.g., a methylene group, and/ or by the oxy oxygen atom of the ester group and wherein at least one of the double bonded carbon atoms bears a hydrogen atom as a substituent.

Of the esters in which the unsaturation is in the alcohol portion of the molecule, preferred are vinyl and allyl esters, especially of straight or branch chained alkanoic or cycloalkanoic saturated monoand dicarboxylic acids containing 1-20 Carbon atoms and substituted by 0-3,

preferably or 1, halogen atoms, preferably chlorine or bromine, and of aryl monoand dicarboxylic acids containing 7-12 carbon atoms and substituted by 0-5, preferably 0, 1 or 2, halogen atoms, preferably chlorine or bromine. I

Examples of such unsaturated esters are compounds of the formula wherein R and R each are hydrogen, alkyl, cycloalkyl, aryl, alkaryl in the corresponding halogenated groups, and a and (1 each are 0 or 1, with the provisio that at least one a and d is 1, and b and c each are 0 or any positive integer.

When R or R' are other than hydrogen, R and R can be straight-chain or branched saturated alkyl of 1-20, preferably 1-12, carbon atoms, or cycloalkyl containing 3-12, preferably -12 ring carbon atoms, 1, 2 or 3 separate or fused rings, and 3-20, preferably 5-12 carbon atoms, unsubstituted or substituted by one or more halogen atoms. Examples of aryl are those containing 6-14 carbon atoms and 1, 2 or more separate or fused rings, unsubstituted, or substituted by unsubstituted or halogenated alkyl or cycloalkyl as defined above.

Examples of alkyl are methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert.-butyl, hexyl, heptyl, octyl and higher straight and branched chain alkyl. Cycloalkyl includes cyclopropyl cyclobutyl, cyclopentyl, cyclohexyl, Z-methyl cyclopentyl, 2,6-dimethylcyclopentyl, 4-methylcyclohexyl, 3,5-dimethylcyclohexyl, Z-methylcyclohexyl, cycloheptyl, cyclooctyl, decahydronaphthyl, and the corresponding groups substituted on one or more ring carbon atoms by alkyl of 1-4 carbon atoms. Aryl includes phenyl, p-diphenyl, naphthyl, ar-lower-alkyl, e.g., p-benzylphenyl, benzyl phenethyl, 2-phenyl propyl and benzhydryl, tetrahydronaphthyl, 6-tetrahydronaphthyl indenyl, dihydroindenyl. Alkaryl includes aryl substituted on one or more ring carbon atoms by alkyl of 1-4 carbon atoms, preferably methyl, e.g., p-tolyl, sym.-xylyl, etc.

When the double bond of the unsaturated ester is positioned on the alcohol side of the ester group, i.e., in the above formula, a=1, b can be 0, or a positive integer, e.g., l, 2, 3-6 or higher. When the double bond is positioned on the acid side of the ester group, i.e., in the above formula, if d: 1, then 0 must be at least 1, i.e., 1, 2, 3-6 or higher.

Examples of preferred unsaturated esters wherein the alcohol portion thereof is unsaturated are vinyl and allyl esters, wherein the vinyl or allyl group is unsubstituted or substituted by one or more straight or branched chain alkyl groups, e.g., containing 1-12 carbon atoms, e.g., methyl, ethyl, propyl, butyl, hexyl, octyl and decyl, or aryl as defined above, e.g., phenyl, or alkanoic and alkanedioic acids containing, e.g., 1-8 carbon atoms, e.g., acetic, propionic, butyric, octanoic, succinic, malonic, fumaric, adipic, and of 'aryl and aralkyl carboxylic and dicarboxylic acids, e.g., benzoic, phenylacetic and phthalic acids and the corresponding halogenated, preferably chlorinated acids, e.g., chloroacetic and dichloroactic acid.

Examples of preferred unsaturated esters wherein the acid portion thereof is unsaturated are alkyl, e.g., of 1-8 carbon atoms, e.g., methyl, ethyl, propyl, octyl, esters of alkenoic acids containing 1-21 carbon atoms, e.g.,-3-butenic, 3-pentenic, 4-pentenic, 3-,,4- and 5-hexenic,'-oleic, brassidic and behenic acids and other straight and branchchained unsaturated acids and the corresponding halogenated, preferably chlorinated or brominated, alkyl esters thereof, e.g., p-chloroethyl esters.

Especially preferred are vinyl and allyl esters of unsubstituted and optionally halogenated monoor dicarboxylic acids. Representative examples of this preferred class are vinyl propionate, vinyl isobutyrate, vinyl stearate, divinyl adipate, methylvinyl adipate, vinyl pivalate, vinyl chloroacetate, allyl propionate, allyl butyrate allyl chloroacetate, allyl dichloroacetate, and diallyl phthalate. Especially preferred are vinyl acetate and allyl acetate.

Other examples of unsaturated esters are crotyl acetate, cinnamyl propionate, isopropenyl benzoate, 2-phenylbuten-(1)-yl-4-acetate, 1,4-diacet0Xybutene-2, oleyl acetate, 3-hexene-1,6-diol distearate, ll-acetoxyundecene-l, octen-(1)-yl-3-butylrate, p-allyl-benzyl formate, 3-viny1- cyclooctyl acrylate, methyl oleate, ethyl undecylenate, the dimethyl ester of dihydromuconic acid (dimethyl ester of 3-hexenedioic acid), or the fi-chloroethyl ester of vinylacetic acid.

If unsaturated esters employed as the regulators are esters of monobasic monounsaturated esters, e.g., those having a carbalkoxy group on one side only of the double bond, e.g., allyl acetate, the polymers produced by the process of this invention possess, on the average, one carboxyalkyl group per macromolecule. However, macromolecules can also be produced which have either no carbalkoxy end group or two carbalkoxy end groups. Macromolecules having two carbalkoxy end groups are always obtained when using as regulators esters having carbalkoxy groups on both sides of the double bond, for example, 1,4-diacetoxybutene-2, the dimethyl ester of dihydromuconic acid and the methyl ester of p-acetoxy-p'- stilbene carboxylic acid. a

A surprising peculiarity of the esters of unsaturated alcohols with b=0 or 1, Le. vinyl or allyl/esters which may be substituted by R as defined before is that they exert, even in very small quantities ranging in the order of mag nitude of catalyst concentration, a favorable influence on the velocity and yield of the polymerization, in addition to controlling molecular weight. This activator effect cannot be explained by means of any of the heretofore known theories regarding the mechanism of the ring-opening polymerization of cyclic olefins.

With the aid of these activators, it is also possible to develop catalyst systems based on tungsten hexachloride and ethylaluminum sesquichloride or diethylaluminum chloride, which normally exhibit only minor catalytic activity, which are highly satisfactory polymerization catalysts. Ethylaluminum dichloride containing catalysts, which have heretofore shown the highest activity, is manufactured in smaller quantities than the two other abovementioned ethylaluminum halogenides and, moreover, can be handled only in dilute solutions, due to its melting point of +32 C. Furthermore, catalysts containing ethylaluminum dichloride have a strong tendency to promote secondary reactions of a cationic type. Thus, for example, they have an alkylating efiect on aromatics and polymerize branched olefins, which can result in gelling.

By employing the activating regulators or regulating activators of this invention, a considerable increase in catalyst activity is always attained, even in the case of catalysts containing ethylaluminum dichloride, so that high conversion rates can be obtained, even when the polymerization is conducted in dilute solutions, which reaction ordinarily progresses very unsatisfactorily, especially in case of cyclopentene. This is also advantageous from the view point of process technique, for it is possible to polymerize a higher proportion of the monomer rather than being forced, as in case of bulk polymerization, to utilize the monomer as the solvent and work with small conversions, due to the viscosity of the thus-produced polymer solution, and to regenerate and recycle the larger portion of the monomer. Besides, especially in the case of cyclopentene, the polymerization need no longer be con- :ducted at the very uneconomical low temperatures of -20 to 30 C. Instead, the same or even still higher yields are obtained under condtions which are technically and economically more advantageous (0 to 20 (3.).

The ring-opening polymerization of cyclic olefins can be conducted by conventional procedures employing known catalysts. Thus, suitable catalysts are supported catalysts containing the metal of Subgroups 5 through 7 of the periodic table, for example, in the form of the carbonyl, sulfide, or superficially reduced oxide on a support such as, for example, aluminum oxide, aluminum silicate, or silica gel. Also suitable are mixed catalysts, e.g., containing a compound of a metal of Groups through 7 of the periodic table and an organometallic compound or hydride of a metal of Main Groups 1 through 3 or Subgroup 2 of the periodic table and optionally, also a compound containing one or more hydroxy and/or sulfhydryl groups. Also suitable are catalysts containing a halide or oxyhalide of molybdenum or tungsten wherein the degree of oxidation of the metal is 4, 5, or 6, and which contain an aluminum trihalide. Preferably, mixed catalysts are employed containing a molybdenum compound or especially a tungsten compound. Preferred organometallic compounds are organolithium, organornagnesium and organoaluminum compounds, especially methylaluminum dichloride, ethylaluminum dichloride, methylaluminum sesquichloride, ethylaluminum sesquichloride, dimethylaluminum chloride and diethylaluminum chloride. Compounds containing one or more OH- and/or SH-groups optionally can be employed concomitantly as a catalyst component, e.g., water, hydrogen sulfide, hydroperoxide, alkyl hydroperoxides, mercaptans, hydrodisulfides, alcohols, polyalcohols, polymercaptans and hydroxymercaptans. Saturated and unsaturated alcohols and phenols, viz, n-propanol, n-butanol, sec-butanol, isobutanol, allyl alcohol, crotyl alcohol, phenol, omand p-cresol, Otand B-naphthol, eugenol and benzyl alcohol, especially methanol, ethanol, isopropanol, or tert.- butanol, are preferred.

The polymerization can be conducted continuously or discontinuously. The reaction temperature can vary widely, e.g., between 70 C. and +50 C. However, temperatures between 30 and +30 C. are preferred.

The amount of regulator which is added and, as a consequence, the molecular weight of the polymers produced,

of low viscosity and syrupy to oily liquids which can be utilized, for example, as drying oils directly, or after an additional reaction, as binders for varnishes or coating agents.

The amount of regulator needed to attain a product of a specific consistency depends, inter alia, on the type of the monomer employed, the type of regulator employed, the catalyst employed, and the selected polymerization reaction conditions. The exact amount of regulator can readily be determined by a few preliminary experiments.

The amount of unsaturated ester employed can vary from about 0.001-20 molar percent, based on the monomer. Generally, the use of about 0.001-5, preferably about 0.003-2, more preferably about 0.01-5 mol-percent, and most preferably about 0.05-2 mol-percent, of unsaturated ester, based on the monomer employed, results in the production of polyalkenamers having molecular weights in the range of commercial elsatomers or thermoplastics. The addition of between about 6 and 20 molar percent, preferably between about 7 and molpercent of the regulator, based on the monomer ,employed, generally is required for the production of lowviscosity to oily products.

These data apply when using regulators which do not simultaneously increase the polymerization velocity and the polymer yield. In contrast thereto, when using activating regulators, about one-tenth of the above quantities often is sufiicient for the preparation of polyalkenamers having molecular weights in the range of commercial elastomers and thermoplastics.

It is to be noted that the unsaturated esters, as Lewis bases (electron donors), form complexes with the other components of the catalyst and thereby can inactivate the latter. Therefore, it is necessary to employ these compounds either in the form of complexes with Lewis acids or to ensure, by an appropriate dosing of the organmetallic compound, that the catalyst is always present in an excess of the oxygen atoms which are effective as electron donors in the regulator compound employed. Otherwise, no polymerization takes place.

Since the activating effect of the esters of vinyl and allyl alcohols is clearly perceptible with the addition of a very small amount thereof, e.g., approximately 1 molar percent of the heavy metal component of the catalyst, especially in case of tungsten compounds and particularly in case of tungsten hexachloride, these activating regulators can also be considered to be components of the catalyst system and can be employed primarily for the purpose of improving yield. Any desired reduction of the molecular weight of the polymer lower than it would be obtained with the use of these additives by themselves, can be achieved by the additional use of other regulators, for example the previously proposed a-olefins. This combination of activating regulators and a-olefins is particularly advantageous when very low-molecular products are to be manufactured, e.g., oils, and no importance is attributed to functional end groups of the polymer because such end groups would not ofifer any special advantages for the intended purpose for which the products are to be used.

It is to be noted that when the conversion of monomer is increased, i.e., when the yield of polymerizate is improved, the molecular weight of the thus-obtained polymer is likewise raised. Conversely, when a substantial increase in conversion is accompanied by only a slight increase in molecular weight (or RSV), this must be still considered to be due to a regulation of molecular weight by the added compound.

The polymerization process of this invention is preferably conducted in solution. For this purpose, inert solvents inert under the reaction conditions are employed,

e.g., benzene, cyclohexane, methylcyclohexane, isopropylcyclohexane, Decalin, hydrogenated kerosene, paraffin oil, methylene chloride, trichloroethylene and preferably hexane, heptane, octane, and perchloroethylene. The

amount of solvent employed can vary widely, e.g., 5 to 2,000% by weight, preferably 50 to 1,000% by weight, based on the monomer employed. Low-molecular oily polymers can also advantageously be prepared without a solvent by mass polymerization, so long as the viscosity of the thus-reacted mixture remains reasonably low.

The amount of catalyst which need be employed is very low. For example, in case of tungsten hexachloride, only about 0.5-2 millimols per liter of reaction volume, or about 1 mol per LOGO-5,000 mols of monomer, is required. When using an activating regulator, this quantity can be reduced to approximately one-tenth the amount, in spite of the improved yield. The concentration of organmetallic catalyst component depends primarily on the purity of the monomer and the solvent employed, i.e., the amount of moisture, peroxides, proton-active impurities, such as alcohols, acids, and other compounds reacting with alkyl metals, such as ethers, amines, ketones, aldehydes, etc., present therein. When the monomer and the solvent are subjected to a very thorough preliminary purification and the reactants are handled with strict exclusion of air in thoroughly dried reactors, molar ratio of heavy metal compound to active alkyl metal, i.e., an alkyl metal which has not been bound or destroyed by impurities or any additional additives present, of about 1:4 to 1:1, preferably less than 1:1, is generally sufficient. Outside of this range, the catalysts are normally less active.

As in the case of regulating the molecular weight of polyalkenamers with monoolefins, surprisingly it is not necessary in the process of this invention that the regulator be present at the beginning of the polymerization in order to obtain the desired effect. The regulator can, if desired, be added after polymerization has begun. All that is required is that the catalyst is still active, i.e., the regulator must be added prior to the inactivation of the catalyst. It is thus possible to use regulators which tend to form homopolymers which are insoluble in the reaction mixture if exposed to the catalyst, either by themselves or in a mixture with cycloolefins at the beginning of the polymerization, and thus inactivate the catalyst by inclusion in the insoluble polymer, or which enter into secondary reaction-s with the catalyst components prior to the actual formation of the catalysts, but which do not react in such a manner with the finished catalyst. The tendency of a regulator to promote homopolymerization or enter into such secondary reactions can quickly be determined by preliminary experiments. Because of this characteristic, it is also possible when an unforseen rise in the viscosity of a polymerization batch takes place, as occasionally happens, to keep the contents of the kettle stirrable by adding the regulator before inactivation of the catalyst, thus avoiding the extensive work connected with emptying a batch which has become too viscous or even gelled.

The preferred catalyst systems employed in the polymerizations of this invention are those comprising (1) a tungsten or molybdenum compound;

(2) an organoaluminum compound;

(3) an ester of vinyl alcohol or of allyl alcohol; and,

optionally,

(4) a compound containing one or more hydroxyl and sulfhydryl groups.

Preferred aspects of the catalyst systems of this invention comprise one or more of any of the following:

(a) component (1) is tungsten hexachloride or tungsten oxytetrachloride;

(b) component (2) is an alkyl aluminum halide, preferably ethylaluminum dichloride, ethylalurninum sesquichloride or diethylaluminum monochloride;

(c) component (3) is vinyl acetate or allyl acetate;

(d) component (4) is ethanol;

(e) the molar ratio of component (1) to component (2) is less than 1:1;

(f) the molar ratio of component (1) to component (3) is less than 100: 1, preferably less than 1.

(g) the molar ratio of component (1) to component (4) is about 120.1 to 1:2; and/or (h) the molar ratio of component (2) to component (3) is greater than 1:1.

After the termination of thepolymerization reaction, the polyalkenamers can be isolated and purified in a conventional manner. If the polyalkenamers are obtained in solution or in the liquid phase, the residues of the catalyst can be removed with an alcohol or other compound having an acidic hydrogen, by washing out the polymer-containing phase with an aqueous or aqueous-alcoholic solution of agents having a dissolving eifect on the catalyst residues, which latter are first present as an alcoholate or a salt of the other compound having an acidic hydrogen atom used to remove the catalyst. Such substances with a dissolving effect on the catalyst are, for example, acids, bases, or complex-forming agents, such as acetylacetone, citric or tartaric acid, ethylenediaminetetraacetic acid, nitriolotriacetic acid, etc. a

After the catalyst has been removed, the polymers are separated by precipitation, e.g., by pouring into a precipitant such as, for example, methanol, isopropanol, or acetone, or distilling oif the solvent, e.g., by blowing in steam, or by introducing the polymer solution through nozzles into hot water. When the polymer can be precipitated from the solution of the monomer in the form of flakes or a powder, the polymer can first be separated, e.g., by filtration, centrifuging, or decanting from the liquid and thereafter treated to remove the'catalyst residues.

In order to protect the polyalkenamers against oxidation, gelling, and other aging phenomena, it is possible to add stabilizers thereto, e.g., aromatic amines or the sterically hindered phenols, at various stages of processing. Also, an optional further purification step can be conducted by reprecipitating the polymer if this should be necessary, to obtain a product of the desired purity. After these operations, the polymer can then be dried in a conventional manner.

In contrast to the previously known polyalkenamers which, although called linear polymers, in reality, are macrocyclic compounds, the polyalkenamers prepared in accordance with the process of this invention are truly linear polymers of a strictly regular structure with exactly defined terminal groups. Such polymers have not heretofore been produced.

The polyalkenamers produced in accordance with the process of this invention are, in contrast to the polymers known heretofore which although called linear polymers are in reality macrocyclic compounds, true linear polymers of a strictly regular structure with exactly defined end groups, which have not been described heretofore.

By the ring-opening homopolymerization according to the process of this invention of monocyclic monoolefins of the general Formula I CH CH Lie polymers of the general Formula II are obtained:

wherein in both instances R is hydrogen or a straightchain or branched saturated alkyl of 1-6 carbon atoms, saturated cycloalkyl of 3-6 carbon atoms or aryl of 610 carbon atoms, and X, m and y have the values given below.

The various I i l X:CH CH OHZX wherein X, y and m have the values given below.

' By the ring-opening homopolymerization of monocyclic diolefins of the general Formula IV CH=CH n 13),

there are obtained polymers of the general Formula V wherein in Formulae IV and V, X, y and 0 have the values given below, and R R R and R which are alike or different, have the same value as R Thus, R and/or R groups can be disposed throughout the polymer molecule. In other words, n of the R groups and/ or o of the R can be hydrogen or 1 to n of the R groups and/ or 1 to of the R groups can also be alkyl or aryl, respectively.

This same applies to R and/or R groups, which likewise can both be hydrogen or either or both can also be identical or different alkyl or aryl groups. Thus, by the ring-opening homopolymerization of unsubstituted monocyclie diolefins of Formula IV wherein R R R and R are hydrogen, there are obtained polymers of the general Formula VI.

Homopolymers of the general Formula VII Rs R7113 n RioRn 12 y VII are produced by the ring-opening polymerization of monocyclic triolefins of the general Formula VIII wherein X and y have the values given below and R R R R R R and R which can be alike or different, have the same values as R The various R R and/ or R groups can be identical or different groups, i.e., all p of the R groups, all q of the R groups and/or all r of the R groups can be hydrogen; or from 1 to p of the R groups, 1 to q of the R groups and/or 1 to r of the R groups can, respectively, be an alkyl or aryl group. The same is true of the R R R and/or R which likewise can all represent hydrogen, or individually or severally, can be identical or different alkyl or aryl groups.

By the ring-opening homopolymerization of norbornene there are obtained polymers of the general Formula IX.

X:CH H-CH X wherein X and y have the values given below.

Polymers containing two or more of the above-described polymer units in a statistical distribution or in larger block sequences are produced during the ring-opening copolymerization of two or more of the above-described cycloolefins in the presence of the claimed polymerization regulators.

In Formulae II, III, V, VI, VII and IX, m is the integer 2 or 3 or an integer from 5 to 10 inclusive; n and 0 each integers from 1 to 7, the sum of which is an integer from 3 to 8; p, q, and r each are the integer 1 or 2; and y is an integer from 2 to about 50,000, preferably 5 to about 20,000.

The novel polyalkenamers of this invention are characterized structurally by their novel terminal groups, These groups are alkylidene radicals derived from the unsaturated ester employed in the polymerization as the polymerization regulator. Thus, in Formulae II, III, V, VI, VII and IX, X is an alkylidene residue corresponding to one of the segments of the unsaturated ester employed during the polymerization wherein the division of the unsaturated ester is effected at the double bond, e.g. an unsaturated ester of the formula 1 2 CH2: and =cH o cocH may be divided in the segments CH and =CH-O-COCH Both segments represent an alkylidene residue.

The solid polymers or oligomers of the general Formulae II, III, V, VI, VII and IX exhibit RSV-values (reduced specific viscosity values) of 0.01-l0.00 dl./g. The low-molecular weight fluid polymers have average molecular weights in the range of about 500 to 25,000. Average molecular weights mean the arithmetic means of the molecular weights.

In former publications Natta and DallAsta stated (Angew. Chem. 76, 765 (1964) and J. Pol. Sci. 6, 2405 (1968)) that polyalkenamers prepared by ring-opening polymerization of cycloolefins have a strictly linear structure. Later on Calderon alleged that those polyalkenamers are in reality macrocyclic compounds (I. Am. Chem. Soc. 90, 4133 (1968)). This proposition was proved by isolation and identification of macrocyclic oligomers with polymerization rates up to 11 (Adv. Chem. Ser. 91, 399 (1969) The novel polyalkenamers can unexpectedly and readily be worked up, as they have a lower reduced melt viscosity. Therefore they may be worked up by lower temperature, e.g., by calendering, rolling or injection moulding, whereby the energy-costs are much smaller..

Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilize the present invention to its fullest extent. The following preferred specific embodiments are, therefore, to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever. Unless stated otherwise, the reduced specific viscosity (RSV) and the gel contents were determined in benzene at 25 C.

EXAMPLES 1-16 AND COMPARATIVE EXPERIMENTS A-E Into a three-tube l-liter glass flask with agitating unit and reflux condenser with a dropping funnel attached thereto were introduced, respectively, ml. (77.8 g.) of cyclopentene and ml. of hexane and were brought under an atmosphere of extremely pure nitrogen, to the reaction temperature by cooling or heating, and are mixed with the components of the polymerization catalyst. After the predetermined reaction period, the catalyst was destroyed by the addition of 50 ml. of methanol containing 3 g. of potassium hydroxide and 2 g. of 2,6-di-tert.-butylp-cresol (Ionol). After the addition of 100 ml. of distilled water and 50 ml. of methanol, so that a second phase containing 50% methanol was formed, the reaction mixture was then further agitated for three hours, to wash out the catalyst residues. The aqueous-methanolic phase was then removed by pipetting and the reaction mixture was washed twice with 50% aqueous methanol. The polymer was then precipitated by pouring the organic phase into 3 liters of methanol. The precipitated product was dissolved once again in 250 ml. of hexane, for purposes of an additional purification, and reprecipitated with methanol to which was again added .2 g. of stabilizer (Ionol). After decocting the polymer for 2 hours with 500 ml. of pure methanol, it was dried for 40 hours at 50 C. in a vacuum drying chamber. The thus-purified polymer was employed for determining the yield and the analytical data. In each case, such a blank test (designated in the table by capital letters) was conducted to exclude sources of errors due to changing impurities in the solvent, the monomer, or the catalyst components, in parallel to the polymerizations employing one of three regulator olefins (numbered examples). The regulators to be tested were admixed with the monomers in the examples. In Table 1, the amount of regulator is set forth in molar percent, based on the monomer employed.

TABLE 1 [Polymerization of eyclopentene (100 ml.=77.8 g. per experiment) in hexane (150 ml. per experimenm .Catalyst system: 0.5-millin1ol of tungsten hexachlon'de/Oh millimol of ethanol/changing amounts of ethylaluminum dichloride; polymerization temperature: 0 0.; polymerization time: 2.5 hours.

Regulator I :EtAlClz in the Amount Experiment 1 catalyst (mol number (mmol) percent) Name Polymer Transcontent Gel Yield RSV (per- (per- (g.) (dl./g.) cent) cent) 12.8 1.8 90 2 16.2 3.0 81 4 v 6.8 3.2 v 91 2 8.1 3.0 80 2 40.9 1.8 74 3 31.7 2.9 66 8 19.8 3 2.5 82 22 11.1 3.0 81 6 40.0 1.0 81 8 19.7 p 1.7 74 4 18.2 2.0 84 7 15.2 3.74 ea 2 34.6 0.82 94 7 22.4 0.77 ca. 100 14 21.7 1.55 73 2 16.3 4.39 94 3 27.4 1.28 91 2 48.5 1.08 81 4 47.0 0.91 76 3 21.8 2.56 87 2 25.8 Methylvinyladipate 25.8- Diallyl sucoinate...

3 14.4- 1.0 Vinyl stearate 14.4 1.0 Octadecen-(9)-yl acetate" 14.4 1.0 Methyl oleate 4 14.4 1.0 Allyl ehloroacetate 14.4 1.0 Allyl' dichloroacetate v 25.8 1- 0 Dia11ylphthalate-... 4' "I 15.4, 1.0 Buten-(1')-yl-3-acetate 25.8 1.0 Divinyl adipate 15.4 1.0 Vinyl isobutyrate 15.4 1.0 2-phenylbuten-(1)-yl-4-aeetate.

decomposed and the polymer was worked up in-the manner described in Examples l-16. There was thus obtained 52.9 g. of a polymer having a reduced specific viscosity (RSV) of 2.1 dl./ g. The polymer contained 32 molar percent of polypentamer units (determined by nuclear resonance analysis), the remainder being polyoctenamer units.

78% of the double bonds thereof detectable by Tultrared analysis were present in the trans-configuration, the re.-. mainder (22%) were present in the cis-configuration.

In a comparative experiment wherein the vinyl acetate and the amount of ethylalurninum dichloride required for .EXAMPLE 19 AND COMPARATIVE EXPERIMENTS K, L, AND M I Use of Diethylaluminum Chloride "These experimerits were conducted analogously to Example 18 and Comparative Experiments G, H, and J, except the same molar amount of diethylaluminum chloride was employed in place of ethylaluminum sesquicompensating the donor eflfect of its ester group :(2 milliw mols) were omitted, there was obtained only 3.4 g. of a. polymer having a reduced specific viscosity of 1.5 dl./g.,

a content of polypentamer units of 57 molar percent and a proportion of trans-double bonds of 84%.

It can be seen from the above that the polymerization of cyclopentene at 0 C. is strongly inhibited by the pres ence of cyclooctene but the addition of an activating regu,

lator, in this case vinyl acetate, overcomes this inhibition.

and makes possible the production of copolymers in high 5.

of vinyl acetate.

Siinilar results are obtained by employing cyclodo decane in place of cyclooctene and/ or allyl acetate in place,

EXAMPLE 18 AND COMPARATIVE EXPERIMENTS E G, H, and I Use of Ethylaluminum Sequichloride chloride. V I I l With thesimultaneous use of ethanol and vinyl acetate, 42.9 g. of a polypentenamer was obtained having a reduced specific yiscosity..of.2.2 dL/g'; and lessthan 2% of gel content. Of the detectable double bonds, 78% were present in the trans-configuration.

In the absence oi ethanol, only 8.3 g. of a polymer was obtained. In the absence of vinyl acetate, the y i eld was only 11.8 g. In the absence of both of these additives, only'16.5.g. of polymer. was produced.

The activating effect of the concomitant use of ethanol and'vinylacetate is especially remarkable and surprising in. this connection since each additive by itself reduces the yield in:polymer.

EXAMPLES 20 2s D COMPARATIVE EXPERIMENTS N, 0, AND P Polymerization of Various Cycloolefins Examples 20-28 and Comparative Experiments N-P were conducted as. described in Examples 1-16 and Comparative Experiments A-E. The solvent, in all cases, was technical hexane (boiling point limits 6870 C.). The amount of this solvent was selected so that the solutions, prior to the polymerization, contained 20% by volume of cyclododecene, 20% by volume of cyclooctene, or 10% by volume of 1,5-cyclooctadiene. The polymerizates were worked up and then analyzed, in the manner already set forth above.

TABLE 2 [Polymerization of various cycloolefins] t Catgysg system: 0.5 millimol of tungsten hexachloride/0.5 millimol of ethanol/ varying amounts of ethylaluminum dichloride; polymerization temperaure:

Regulator Pol er EtAlCh Polymeriym in the zation Mol RSV 'Irans- Gel Experiment catalyst time per- Yield (dl./ content (pernumber Monomer Ml. G. (mmol) (hours) cent Name (g.) g.) (percent) cent) 2 102 r 1 0 v1 1 t t ny ace 3 e 21.-- 84 10.6 0 5 i 1 0 Methyl oleate 13.7 0.77 22... 10.6 1 0 Octadecen-(9)-yl acetate 21.6 0.90 e e 2 5 1 o o t 1) 13 t to 35': cen- -y -aeea 24..- 87 3.2 2 5 1.0 Allylchloroacetate 57.5 1.10 25. 8.2 1 0 Vinyl stearate--- 45.3 1.66 P 10 14111 t b t 2 it? ace oxy u enefgg 100 12.1 0 1 0 Vinyl isobutyrate 63.8 1.3 12.1 1 0 Ethyl undecenoate. 28.5 0.56

Norm-In Examples 20-25 and Comparative Experiments N and 0, the RSV-values were measured in Decalin" at 135 C.

COMPARATIVE EXPERIMENT SERIES Q-W 20 What is claimed is:

Comparative Experiments Q-W were conducted in the A process.for the Production 9 pplyalkanamfars by manner described in Examples 1-16 and Comparative the j' rmg'openmg poiyglenzatlon of cychc Experiments AE. For each experiment, 100 ml. (87.5 fins employing a gatzilyst Cntam.mg a meta} of subgmtlps g.) of cyclododecene was employed as the monomer and 5 to 7 of peylodlf: Table whlch comprises conductmg 150 m1 of technical hexane (boiling point limits: 25 the polymer zation 1n the presence of an unsaturated 3 Q) was employed as the solvent The various com carboxylic acid ester whereln the ester group 1s separated jugated dienes were utilized in varying amounts. The from; double s by at least one molar percent of diolefins set forth in Table 3 refers, in met yene group or smgle on ed oxygen atom of the ester group and at least one of the carbon atoms each case, to the cycloolefin employed. For each expenment, there was employed as the catalyst 0.5 millimol having the double bond has at least one hydrogen atom.

of tungsten hexachloride, 0.5 millimol of ethanol, and A Process according to claim 1 wherein the cyclic 3 millimols of ethylaluminum dichloride. In all experif is Selected from the group f f 0f yments the polymerization ti was 25 hours at 20 C, 0110, monounsaturated olefins contammg 4 and 5 or from The polymerizates were worked up in a manner d c ib d 7 to 12 ring carbon atoms and monocyclic, diunsaturated above and then analyzed. olefins and contains from 7 to 12 ring carbon atoms.

TABLE 3 Polymer Experiment Mol. series Conjugated diolefin per- Yield, RSV, Trans, number name cent g. Percent dL/g. percent R Isoprene.. 46.1 53.0 2.25 46 5 N o polymer 8 2,3-dimethylbutadiene 21.6 24.8 2.15 4h 5 N0 polymer 10 No polymer U Cyclnpentndiana 45. 4 52. 3 2. 26 52 V 1,3-cyclododeeadiene 47.2 54.2 2.10 43 w 1,3-cycl 26. 5 30.5 1. 03

1 Too little substance.

I Polymer contains insoluble components. N one-All RSV-values were measured at 135 0.111 Decalin."

The preceding examples can be repeated with similar 3. A process according to Claim 1 wherein at least success by substituting the generically or specifically detwo of the substituents on the double bonded carbon scribed reactants and/0r operating conditions of this a ms are hydrogen atoms. invention for those used in the preceding examples. A Process accordmg to Claim 1 Wherem t e ester 7 is a vinyl ester. 5. A process according to Claim 4 wherein the ester is a vinyl ester of an alkanoic or cycloalkanoic saturated From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invennon and Wlthout departing from the Spmt and monoor dicarboxylic acid containing 1-20 carbon atoms scope thereof, can make var1ous changes and modificaand Substituted by halogen atoms or f an aryl tions of the invention to adapt it to various usages and mono. r dicarboxylic acid containing 7-12 carbon atoms conditions. and substituted by 0-5 halogen atoms.

6. A process according to Claim 5 wherein the ester is vinyl acetate.

7. A process according to Claim 1 wherein the ester is an allyl ester.

8. A process according to Claim 7 wherein the ester is an allyl of an alkanoic or cycloalkanoic saturated monoor dicarboxylic acid containing 120 carbon atoms and substltuted by 3 halogen atoms or of an aryl monoor dicarboxylic acid containing 7-12 carbon atoms and substituted by 0-5 halogen atoms.

9. A process according to Claim 8 wherein the ester is allyl acetate.

10. A process according to Claim 1 wherein the unsaturated ester is added after the polymerization is initiated and before the polymerization catalyst is inactivated.

11. A process according to Claim 1 wherein the amount of unsaturated ester employed is about 0.001-20 molar percent, based on the monomer.

12. A process according to Claim 11 wherein the amount of unsaturated ester employed is about 0.001- molar percent, based on the monomer.

1.3. A process according to Claim 12 wherein the amount of unsaturated ester employed is about 0.003-2 molar percent, based on the monomer.

14. A process for the production of syrupy and liquid polyalkenamers according to Claim 11 which comprises employing as the monomer cyclobutene, cyclopentene, cyclooctene, a mixture of cyclobutene and cyclopentene,

a mixture of cyclobutene arid cyclooctene, or a mixture of cyclopentene and cyclooctene and employing about 6-20 molar percent, based on the monomer, of the unsaturated ester.

15. A process according to Claim 14 wherein about 7-15 molar percent, based on the monomer, of the unsaturated ester is employed.

16. A process according to Claim 1 wherein the polymerization is conducted in the presence of an amount of a Lewis acid selected from the group consisting of organometallic compounds from a metal of main Groups 1 through 3, or Subgroups 2 of the Periodic Table equivalent to the ester group content of the unsaturated ester.

17. A process according to Claim 16 wherein the organometallic compound employed as the Lewis acid is a component of the catalyst system.

References Cited UNITED STATES PATENTS 3,157,708 11/1964 Mun Ley et a1. 2606-66 A 3,424,774 1/ 1969 Tornquist 260-683.15 R

3,798,175 3/1974 Streck et al. 252429 B FOREIGN PATENTS 1,394,380 2/1965 France 260-677 R 1,098,340 1/ 1968 Great Britain 260677 R DELBERT E. GANTZ, Primary Examiner J. M. NELSON, Assistant Examiner U.S. Cl. X.R. 

1. A PROCESS FOR THE PRODUCTION OF POLYALKENAMERS BY THE CATALYZED RING-OPENING POLYMERIZATION OF CYCLIC OLEFINS EMPLOYING A CATALYST CONTAINING A METAL OF SUBGROUPS 5 TO 7 OF THE PERIODIC TABLE WHICH COMPRISES CONDUCTING THE POLYMERIZATION IN THE PRESENCE OF AN UNSATURATED CARBOXYLIC ACID ESTER WHEREIN THE ESTER GROUP IS SEPARATED FROM THE DOUBLE BONDED CARBON ATOM BY AT LEAST ONE METHYLENE GROUP OR THE SINGLE BONDED OXYGEN ATOM OF THE ESTER GROUP AND AT LEAST ONE OF THE CARBON ATOMS HAVING THE DOUBLE BOND HAS AT LEAST ONE HYDROGEN ATOM. 